不同风载下桁架式海上风力机地震动力学响应

Seismic Dynamic Response of Jacket Offshore Wind Turbines Under Different Wind Loads

为研究风载荷对地震发生时桁架式海上风力机动力学响应的影响,以NREL 5 MW海上风力机为研究对象,建立桁架式风力机有限元模型,采用p-y曲线描述柔性海底土壤与桩基间的相互作用。基于SMOOTH湍流风谱模型求解风载荷,并计算正常运行、停机及紧急停机工况下风力机支撑结构的瞬态动力学响应。结果表明:风载荷对风力机支撑结构影响十分显著,且不同运行工况的支撑结构响应特性有较大差异。地震的发生会导致局部剪应力及应变能波动频率和幅值激增,采用紧急停机的方式可有效削弱风-地震联合作用对风力机叶片及支撑结构的影响。地震发生后的60 s,支撑结构局部剪应力峰值下降7.7%,平均值下降87.5%,集中于风力机塔架与桁架结构衔接处的应变能峰值下降14.6%。

To study the influence of wind load on the dynamic response of jacket offshore wind turbines during the occurrence of an earthquake, the NREL 5 MW offshore wind turbine was taken as the research object, and the finite element model of truss wind turbine was established. The p-y curve was used to describe the interaction between flexible seabed soil and pile foundation, while the SMOOTH turbulent wind spectrum model was applied to solve the wind load, and the transient dynamic response of the wind turbine supporting structure was calculated under normal operation, shutdown and emergency shutdown conditions. Results show that the wind load has a significant influence on the supporting structure of a wind turbine, and the response characteristics of the supporting structure vary greatly under different operating conditions. The occurrence of an earthquake will lead to a surge in the frequency and amplitude of local shear stress and strain energy. The emergency shutdown can effectively weaken the influence of wind-earthquake interaction on the wind turbine blades and the supporting structure. 60 s after the earthquake, the peak value of local shear stress in the supporting structure would drop by 7.7%, with an average reduction by 87.5%. The peak value of strain energy at the junction of wind turbine tower and jacket structure would drop by 14.6%.